中文摘要：

采用直流电弧等离子体法制备Sn纳米粒子,通过搅拌铸造的方法添加到AZ31镁合金当中。通过金相、扫描电镜和拉伸性能测试等技术,考察了添加不同量的Sn纳米粒子对AZ31镁合金铸态组织和力学性能的影响。结果表明,添加Sn纳米粒子可抑制共晶相以层片状析出,促进β-Mg17Al12相以骨骼状分布在晶界处。重要的是,观察到Sn纳米粒子在镁合金中生成了纳米尺寸的Mg2Sn颗粒,但主要以颗粒团簇的形式存在。过量添加Sn纳米粒子,会使Mg2Sn纳米级颗粒团聚严重,降低AZ31镁合金的力学性能。结果表明,添加1%Sn（质量分数）纳米粒子,AZ31镁合金的力学性能最优。

英文摘要：

Sn nanoparticles were prepared by the DC arc plasma method and then they were introduced into the AZ31 magnesium alloy melt by stir casting. The influence of the different addition proportions of Sn nanoparticles on as-cast microstructures and mechanical properties of AZ31 magnesium alloy were investigated by metallography, scanning electron microscopy（SEM） and tensile tests. The results show that the addition of Sn nanoparticles inhibits the eutectic phase precipitation in the shape of lamellar, but promotes β-Mg17Al12 distribution at the grain boundary in the shape of bone. Importantly, we have observed that Mg2Sn particles are formed from the Sn nanoparticles, but the Mg2Sn particles mainly exist in the form of particle clusters. With the excessive addition of Sn nanoparticles, more severe Mg2Sn nanoparticle clusters appear and the mechanical properties decline. In the present study, the most superior mechanical properties of the AZ31 magnesium alloy can be achieved when the proportion of Sn nanoparticles is about 1 wt%.